Levulinic acid, or 4-oxopentanoic acid, is an organic compound with the formula CH3C(O)CH2CH2CO2H. Levulinic acid as such is used as preservative in food and cosmetic applications. It can be derived from degradation of cellulose that is for example present in agricultural waste products, waste from the paper industry or municipal waste but also in lignocellulosic biomass such as wood and grass.
Levulinic acid is a precursor to pharmaceuticals, plasticizers, and various other additives.
Biofuels can also be prepared from levulinic acid including methyltetrahydrofuran (MeTHF), gamma-valerolactone, and ethyl levulinate.
In the prior art several processes for the production of levulinic acid are described.
Levulinic acid can, for example, be produced from diethyl acetyl succinate as, for example, described in U.S. Pat. No. 5,189,215. Diethyl acetyl succinate can be made from diethyl maleate, which in general is derived from petrochemical based maleic acid anhydride.
Another process for the production of levulinic acid is a process that produces levulinic acid from furfuryl alcohol or its esters. An example of such a process is described in U.S. Pat. No. 4,236,021. Furfurylalcohol is converted at 125° C. to butyl levulinate in the presence of an alcohol, such as butylalcohol, with HCl as catalyst. Butyl levulinate is isolated via distillation. After hydrolysis in an aqueous environment levulinic acid is obtained.
A third process for the production of levulinic acid is by acid catalyzed hydrolysis of C6 carbohydrate-containing feedstocks. The production of levulinic acid by acid catalyzed hydrolysis of C6 carbohydrate-containing feedstocks is described e.g. in WO2010/030617, US2010/312006, U.S. Pat. Nos. 5,608,105, 4,897,497 and 6,054,611.
WO 2014/087013 describes a process to isolate levulinic acid from compositions made by acid hydrolysis of lignocellulosic biomass. However, the levulinic acid compositions produced contain large quantities of angelica lactone which can be detrimental. Additionally, there is no formic acid in the final product.
For the purpose of the present invention levulinic acid is produced by acid catalyzed hydrolysis of a C6 carbohydrate-containing feedstock.